1. Field of Invention
The present invention relates to composite fiber reinforced polyethylene and a method of manufacturing the reinforced polyethylene.
2. Description of the Related Art
Methods for producing reinforced polyethylene have been difficult due to the nonpolar surface of both the polyethylene and cellulose fibers. This phenomena prohibits chemical coupling and reduces mechanical mixing between the two materials. Past efforts include combining materials into polyethylene by mixing so as to cause intertwining of the molecules. Proper intertwining requires generating sufficient mix and one hundred percent "wetting of the fiber." The wetting of the fiber refers to completely surrounding fiber molecules with polyethylene molecules.
The mixing method incorporated first added lubricants such as a wax or paraffin based low molecular weight polyethylene resin to the polyethylene, followed by injecting the cellulose fibers downstream into the melt flow of the resin when it was sufficiently molten to flow around the fibers. Without a molecular coupling, the resin that surrounds the fiber has a dramatically higher rate of expansion, causing a pull away from the surfaces between the resin and the fibers. This "pulling away" between the two surfaces causes microscopic points of leverage, resulting in a weak composite matrix. A weak composite matrix results in lower impact values and reduced structural rigidity. Additionally, the wax based polyethylene has a dramatically lower molecular weight and is, therefore, substantially weaker.